Feeding mechanism for a firearm



April so, 1957 Filed Nov. 29. 1951 lll "l /V /fZZ////// J. R. BIRD 2,790,353

FEEDING MECHANISM FOR A FIREARM 4 Sheets-Sheet 1 Apnl so, 1957 J. R. BIRD FEEDING MECHANISM FOR A FIREARM Filed NOV. 29, 1951 4 sne'ets-shee. 2

J. R. BIRD FEEDING MECHANISM FOR A FIREARM April 30, 1957 4 Sheets-Sheet. 5

Filed Nov. 29, 1951 April 30, 1957 J. R. BIRD FEEDING MECHINISM FOR A FIREARM 4 Sheets-Sheet 4 Filed Nov. 29, 1951 nited States 2,790,353 FEEDING MECHANISM FOR A FIREARMV John R. Bird, Belmont, Mass., assignor to the United States of America as represented by the Secretary of the Army The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to the feeding of ammunition in automatic rearms and is more particularly directed to irnproved means for increasing the rapidity with which individual rounds are loaded into a firing chamber.

On automatic rearms greater than cal. .50, the length and weight of the individual rounds render it exceedingly difficult to obtain the high rates of re found in the smaller caliber firearms. Attempts to increase the rate of re of the above-mentioned firearms have heretofore been chiefly directed to improving the speeds of firing and extracting the fired round. One such firearm in which relatively high rates of re have been obtained is the German MG-213 type wherein there is provided a re volving drum having a plurality of radially disposed ring chambers.

In the feeding of automatic iirearms of the MG-2l3 type, it has been found because of the length and the weight of the complete round, that the time necessary to load the round into the chamber is necessarily longer than either the time of firing or extracting.

The invention presently to be described increases -the rate of ire of drum type firearms by shortening the time necessary to insert a complete round into the chamber. In this device, separate loading of the propelling charge and projectile is utilized, ythe projectile being loaded from and into the front of the chamber at the same time the propelling charge is being loaded vfrom and into the rear of the chamber. This loading concept is equally applicable to those firearms wherein the firing chambers are formed in a transversely reciprocating breech element.

Accordingly an object of this invention is to provide a feeding means for the simultaneous loading of a projectile and a propelling charge into the front and rear portions of a chamber, respectively, in a revolving drum or movable breech element type of automatic firearm thereby forming a complete round therein immediately prior to the firing thereof.

An object of this invention is to provide an improved feeding means for automatic firearms whereby with a minimum of feeding length required due to the round being fed in two sections an increased rate of fire is obtainable with a lighter and shorter firearm.

Another object of this invention is to provide an improved feeding means for a lirearrn of the type wherein a pair of tiring chambers are provided in a transversely reciprocating breech element and dual loading and firing of ammunition is obtained by loading one chamber on either side of the barrel while a round of ammunition is being fired in the other chamber.

A further object is the provision of a gun wherein a projectile and its propelling charge are independently and preferably simultaneously loaded from different directions into a movable breech element'into cooperative relation to form a complete round therein prior to, or

arent during, movement of the element to convey the round to firing position.

Yet another object is to provide a gun of the type mentioned in the preceding paragraph which is recoilless.

A still further object is the provision of a recoilless gun wherein the breech chamberris divided into two parts and, more particularly, one wherein the chamber receiving the projectile and its propelling charge, are in a movable breech element, while the part forming the eX- pansion chamber and reaction jet are formed in or xedly related with the breech casing or receiver.

A further object is the provision of a gun as in thev preceding object wherein the round of ammunition formed by the propelling charge and projectile is moved from a loading position into a tiring position between the breech end of the barrel and the aforesaid expansion chamber to form a gas tight connection between the bal'- rel and chamber.

Other objects and advantages of the invention will appear from a description of a preferred embodiment as shown in the accompanying drawings in` which:

Figure l is a longitudinal sectionalized view of the drum type of mechanism using conventional type metal cartridges and taken along line 1-l of Figure 2;

Figure 2 is a cross-sectional View taken along the line 2 2 of Figure l; Y

Figure 3 is a cross-sectional view taken along the line 3 3 of Figure l;

Figure 4 is a side elevational view of the drum type of mechanism for a recoilless type of weapon;

Figure 5 is a longitudinal sectionalized view of Figure 4 taken along a section line similar to Figure l to show the electrically tired ammunition utilized therein;

Figure 6 is a partial sectionalized View showing the obturating sleeve in the red position;

Figure 7 is a cross-sectionalview taken along the line 7-'7 of Figure 4;

Figure 8 is a cross-sectional View taken along the line 8-8 of Figure 7;

Figure 9 is a longitudinal sectionalized view of a irearm having a pair of tiring chambers in a transversely reciprocating breech element and adapted for the feeding mechanism of this invention;

Figure l0 is a cross-sectional view taken along the line '10. 10 of Figure 9;

Figure l1 is a cross-sectional view taken along the line lll- 11 of Figure 9; and,

Figure l2 is an enlarged cross-sectional view of the rear end of the drum of Figure 5 showing the means for effecting the electrical discharge of the propelling charges.

Referring to Figures 1, 2, 3 and 6, there is shown in assembled relation a receiver or breech casing 12, a rotatable drum 13 and a barrel 14. The receiver 12 comprises a rearwardly extending housing 15 and a circular ange 16 on the forward end of receiver 12. Housing 1S is provided with a circular flange portion 18 on the forward end which is diametrically equal and oppositely disposed to flange 16. Flange 16 and flange port on 18 are provided with corresponding slots 19 on the periphery thereof to receive a plurality of supporting bars i7 therein which are fastened thereto by screws 20, or may be welded if so desired. A conventional type of tiring mechanism and means for rotating drum 13 are contained in housing 15 but are not shown as they do not form any part of this invention. A longitudinal axial bore 21 is provided in housing 15 for a purpose to be explained later. Vertically above and parallel with bore 21 a firing pin tunnel 22 is provided to receive a iring pin 25. Angularly disposed and parallel with bore 21 in housing 15 there is provided acartridge case feeding bore or recess 24 for slidably receiving a plurality a of longitudinally disposed cartridge cases 25. Housing is also provided with an ejection mechanism for the ejection of fired cartridge cases 25. However, such mechanism is not shown as it does not form any part of this invention.

Flange 16 is provided with a threaded hole 26 axially aligned with tunnel 22 for receiving a threaded portion 27 of barrel 14. An axial bore 28 is provided in flange 16 in alignment with bore 21 of housing 15 to receive a rotatable shaft 29. A threaded hole 34) is provided in flange 16 to threadably receive a projectile tube 31 and is in axial alignment with recess 24 of housing 15. Projectile tube 31 is provided with a longitudinal bore 37 therethrough to slidably receive projectiles 38.

Drum 13 is secured to shaft 29 by a key 32 for rotation therewith. Drum 13 is provided with three chambers 33 which are an'gularly positioned equidistant apart as shown in Figure 3. However, it must be understood that a greater number of chambers can also be used. Onthe frontend of each chamber 33 an enlarged counterbored hole 34 is provided to slidably receive an obturating sleeve 35; A. pair of piston rings 36 are resiliently mounted. on sleeve 35 to obtain a better gas seal, as will be explained later;

rPower-operated and synchronized rammers 49 and 41 are. employed in the front end of tube 31 and the rear end of recess 24 respectively to advance projectiles 38 and cartridge cases 25 into the chamber 33 of drum 13 aligned therewith, resulting in assembling a complete round of ammunition prior to the drum being rotated to firing, and ejecting simultaneously. Therefore, while the i half portions of the round are being simultaneously assembled in their respective chamber, another previously assembled and chambered round is being fired and also the previously tired round is being ejected from one of the remaining chambers.

Referring to Figures 4, 5, 7 and 8 there isV shown in assembled relation an automatic gun of the recoilless type to which this improvement of 'feeding means is applicable and is within the scope of this invention. The complete round utilized comprises a projectile 51 and a combustible or disintegrating propellant charge 52 adapted to be electrically tired. A receiver 53, as shown, differs from the above-described receiver 12 in that' mechanical firing and ejecting mechanisms are not necessary and/or used.`

Receiver or breech casing 53 comprises a rearwardly extending housing 54 and a circular flange 55 on the front end of casing 53. Housing 54 is provided with an axial bore 56 for a purpose to be later explained. Vertically above bore 56, a longitudinally extending boss 57' is provided having an expansion chamber 54a and a venturi orifice 58 therein to allow a suflicient amount of the gases from a fired round to expand and escape rearwardly, thereby stabilizing the gun against recoil, Angularly disposed from and parallel with boss 57 there is provided a tube 59 having a recess 60 therethrough for holding a plurality of propelling charges therein. Housing 54 is provided with a ange portion 61 on the front end thereof which is diametrically equal and oppositely opposed to flange 55. Flange 55 and flange portion 61 are provided with a plurality of corresponding slots 43 on the periphery thereof to receive supporting bars 44 therein which are fastened thereto by screws 45. Portion 61 is provided with ramp or cam surfaces 62 on the front surface thereof as shown in Figures 4, 7 and 8 for a purpose to be later explained. Circular flange 55 is provided with cam surfaces 63 on the rear surface thereof and oppositely opposed to cam surfaces 62. Bore 42 of flange 55 is in alignment with bore 56 of housing 54 to receive a rotatable shaft 64.

A drum 65 is secured lto shaft 64 by a key 66 for rotation therewith. Drum 65 is provided with three or more chambers 67 which are angularly positioned equidist-ant apart. Each chamber 67 is counterbored at both the front and rear endsas shown at 68 and 69 to slidably receive obturating sleeve 70 and 71, respectively. Sleeves 70 and 71 are provided with conventional piston rings resiliently mounted thereon. Each propellent charge 52 is provided -with a conventional squib 110 in the interior thereof which is in electrical connection with a pair of metallic bands 111 formed about the exterior periphery of charge 52. Each obturating sleeve 71 is provided with a suitably insulated section 112 about the exterior periphery thereof. A pair of annular metallic bands 113 are embedded in insulation 112 to provide an electrical connection between leads 72 and suitably insulated leads 114 passing through the walls of sleeve 71. The opposite ends, of leads 114 are arranged to contact bands 111 on charge 52 and thereby complete the electrical circuit when sleeve 71 is returned to the firing position within counterbored portion` 69 of chamber 67. Bands 113` arey suitably insulated from the interior wall surfaces of chamber portion 69 and bands 111 are similarly insulated' from the interior periphery of obturating sleevel 71. In close proximity to the rear opening of each chamber, there is provided a pair of spring-biased terminalsk 73 which arev connected to lead wires 72. Vertically above bore 56 of housing 54 there is provided a pair of xed terminals 74 on the forwardv face of flange portion 61 which are electrically connected to an electrical source (not shown) by lead wires 75.

The operation of this type of gun when using this inventionA is similar to. the functioning cycle of the previously described gun except that the ammunition is electrically diSCharged and thereby eliminates the necessity of the mechanical rinfg mechanism and also the ejecting means as the propellent charge 52 is of the distintegrating type. Controlled' electrical impulses from a source (not shown) pass through wires 75, fixed terminals 74, terminals 73, lead wires 72 and leads 114 thereby igniting the charge 52 when in the battery position. The rear obturating sleeve 71 is propelled rearwardly at the time of the explosion to close the, gap between the rearward face of the rotary drum and casing, and the front sleeve 70 is propelled forwardly, as previously described for sleeve 35. The cam surfaces 62 and 63v are provided Vto properly seat the projectile 51 and propelling charge 52, respectively. while the drum is, being rotated. These cam surfaces are also applicable to the previous gun described as they also cam the obturating sleeves back to their normal position. It is contemplated however, that the frictional forces exerted upon sleeves 70 and 71 at the time the projectiles and propelling charges are rammed', may be suicient to move the sleeves into retracted position within the drum. The three or more chambers are used for loading, firing, and cooling, or if preferred, two chambers oppositely opposed can be used instead rotating the drum for each cycle of functioning;

It will be noted that, as each chargeSZ is ignited, a portion of theA gas is discharged rearwardlyl and expands in chamber 54a to momentarily lower the effective velocity, and is then propelled atmuch higher velocity through venturi 58 to effect a thrust, forwardly upon the gun, Vequal to the rearward force of recoil, whereby external forces, otherwise caused by recoil, are eliminated, so that guns of relatively large caliber may be fired from the shoulder or supported by light mounts only. A gun of the recoilless type having the same diameter of expansion chamber as the bore of the barrel, that is, a chamber without yconstriction orV throat, will be recoilless but relatively ineticient in utilization of propellant. I A gun wherein the venturi throat is constricted out without an enlarged expansion chamber, will be partially recoillness 'and somewhat more efficient than inthe rst case. Much greater efciency and a completely recoilless weapon is attained, however, by the preferred form of an expansion chamber enlanged in cross sectional area over the corresponding section of the barrel bore, followed by a venturi throat of reduced size from that of the barrel bore, andleading to an enlarged or rearwardly-flared nozzle.

Referring to Figures 9, and l1 there is shown in assembled relation an automatic gun of the recoilless type havin-g a transversely reciprocating slide or breech element wherein the chambers move in translation only either vertically or horizontally, the dual chambering of the ammunition f being 'accomplished alternatively on either side of the weapon. The improvement of feeding hereinbefore disclosed is also applicable to this type of gun and is within the scope'of this invention.

There is illustrated particularly in Figure 9, a reeciver or breech casing 80 comprising a body portion 81., a rear portion 82 and a front portion 83. A barrel 84 is threadably secured to front portion 83 in the center thereof and extends forwardly therefrom. Front portion 83 is provided with a pair of forwardly extending projectile tubes 85 positioned on each side of and an equidistance apart from the barrel S4. Each tube 85 is provided with a longitudinal bore 86 therethrough which slidably receives projectiles 51. Rear portion 82 is provided with aA rearwardly extending boss 87 which may be integrally formed therewith or threadably secured thereto, as desired. Bossv 87 isprovided with an expansion chamber 87a and a ven-.

turi orifice 88 extending longitudinally therethrough and in axial alignment with barrel 84. Portion 82 is provided with a pair of rearwardly extending cartridge tubes S9 Vpositioned on each side of and an aquidistance apart from boss 87. Cartridge tubes 89 are provided with a longitudinal recess 90 therethrough to slidably receive a plurality of propelling charges 52 and are in exact axial alignment with projectile tubes 85. A rearwardly extending fiat web 91 joining tubes 89 and the rear surface ofportion 82, is provided for a purpose to be later explained.

Body portion 81 comprises a box-like member having two side walls 92 with portions 82 and 83 forming the rear and front walls, respectively. The inwardly facing surface of portions 82 and S3 are each provided with a pair of raised ribs 93, as shown in Figures 9 and l0 which extend transversely therewith. A breech element '94 is slidably mounted on ribs 93 for transverse reciprocating movement within body portion S1. Element 94 is provided with two chambers which are identical in structure as the one described above for the rotating type of drum 65. A pair of spring-biased electrical terminals 102 is provided above each chamber with lead wires 103 connected to the `chamber which is electrically contacted by an electrical source 194 when in the breeched or tiring position.

A cam surface or ramp 95 is provided on each side of the barrel and venturi orifice on the front and rear inside wall surface, respectively, of body portion 81 to properly seat the projectile and propelling charge when thev breech element `9d is reciprocated to a ring position. These cam surfaces also return the obturating sleeves to their normal position. it is contemplated however, as in the model shown in Figuresl through 8,that the forces of ramming may be suflicient to return the obturating sleeves to retracted position. To prevent the projectile and propelling charge from entering the body portion 81 when the breech element 94 is not in the chambering position, a bafde 96 is secured to each corner of element 94 for reciprocating movement therewith. A pair of slots 97 is provided in each side wall 92 Vto slidably receive baille 96. A stud 98 is secured to web 191-and a` lever 99 is pivotally mounted thereon which is operated by a suitable mechanism (not shown) located in the rear of the-gun to reciprocate element 94 in body portion 81. A stud 100 secured to breech element 94 and slidably connected in an elongated slot 101 in the free end of lever 99 permits the above-mentioned reciprocation.

From the foregoing description it is thus readily apparent that there is herein provided a simple and economical means for feeding ammunition into various types of automatic firearms. Only a few types of rearms applicable to receive this invention have been mentioned above, it being understood that the scope of this invention includes any firearm either semi-automatic or automatic utilizing automatic loading. It therefore should be apparent to any one skilled in the art that this invention utilizing the loading of ammunition as above described, shortens the time for loading the complete round, shortens the overall length of the firearm and shortens the feeding stroke thereby providing a higher rate or re in an automatic firearm than the more conventional designs.

This invention in performing a multiplicity of different 'functions simultaneously also provides a higher rate of re in an automatic firearm than the more conventional designs in which only one chamber is present and the operations of ring, extracting, ejecting, -and re-loadingy must be performed in successive operations during one cycle of the rearm. i

In the claims, the term cooperative relation as re-A ferred to the projectile and propelling charge within theV ring chamber, means a relation or position wherein ignition of the charge will propel the projectile along the barrel of the gun. Y

I claim:

1. In a gun of the recoilless type, a breech casing, a

barrel, a movable breech element having a plurality of tiring chambers each being movable from a loading position to a ring position, means for separately ramming a projectile and a propelling charge into opposite ends of one of said chambers when in said loading position thereof, means xed to said casing and forming a rearwardly-directed discharge passageway in axial alignment with said firing chamber in said firing position thereof, said passageway including an enlarged expansion chamber immediately rearwardly of said firing chamber, said expansion chamber tapering to a venturi discharge passage, and cam means on said breech casing for combining the projectile and the propelling charge into a complete ammunition round during movement of said ring chamber from said loading position to said tiring position.

2. In a gun, a lixed breech casing, a barrel secured to and extending forwardly from said casing, a housing secured to and extending rearwardly from said casing in axial alignment with said barrel, -a drum rotatably sei cured to said casing between said barrel and said housing,

ment of the loaded one of said chambers to the ring y position, said housing having a posterior chamber portion comprising an expansion area and a venturi passage extending rearwardly therefrom, and an obturating sleeve in the front and rear ends of said anterior chamber portion slidablylresponsive to the discharge of the projectile and propelling charge, said forward obturating sleeve, being mov-able into c-ontact with the breech end of said barrel and said rearward obturating sleeve being movable into contact with the forward end of said housing whereby saidf interiorV chamber portion forms a continuation of said barrel with said posterior chamber portion.

3. kIn a gun, the combination of a breech casing, a barrel projecting forwardly from said casing, a breech element rotatably mounted in said casing Vand having a plurality of firingA chambers successively rotatable between loading and ring positions in response to the discharge of a round of ammunition, means rearwardly of said breech element for feeding a cartridge case into the rear end of each firing chamber subsequent to the movement thereof into loading position, means forwardly of said breech element for simultaneously feeding a projectile into the front end of the same chamber, and means for combining said cartridge case and said projectile to form a complete roundof ammunition during movement `of said same chamber from loading to tiring position.

4. In a gun, the combination of a breech casing, a barrel projecting forwardly from said casing, a breech element slidably mounted in said breech casing for transversemovement. therein in response to the discharge of a roundV of ammunition, means rearwardly of said breech element for holding7 a plurality of propelling charges, means forwardly ofy said breech element and in axial alignment with said propelling charge holding means for holding a plurality of projectiles, said breech element having a plurality of parallel firing chambers so disposed that one of said chambers is in a tiring position in axial alignment with said barrel when another chamber is in a loading position in axial alignment with saidl means for holding the propelling charges and projectiles, means for simultaneously feeding -a propelling charge and a projectile into said ring chamber in the loading position, means for combining the propelling charge and projectile during movement of each of said firing chambers from loading to firing position, and means for blocking the feeding of the propelling charges' and projectiles during the transverse movements of said breech element. f

5. In a gun, a breech. casing, a barrel xedly secured in said casing, firing means inthe rear of said casing in axial alignment with said barrel, a breech element movably disposed between said barrel and said firing means, said element having a plurality of ring chambers movable from loading to firing position in response to the discharge of a round of ammunition, said breech casing having a longitudinal recess in the rear end thereof for holding a plurality of cartridge cases, said breech casing having a longitudinal tube in the forward end thereof for holding a plurality of projectiles in axial alignment with s-aid cartridge case recess, means for advancing the leading cartridge case into the rear end of one of said firing chambers when in the loading position thereof while simultaneously advancing the leading projectile into the front end of the same oneof said firing chambers, and cam means on the inner front and rear surfaces of said breech casing for combining the cartridge case and projectile in said loaded ring chamber during the movement thereof from loading to tiring position.

6. In a gun, a breech casing, a barrel lixedly secured in said casing, a breech `element slidably mounted in said breech casing for transverse movement therein in response to the discharge of a round of' ammunition, said breech casing having a. pair of longitudinal recesses in the rear end thereof for holding a plurality of propelling charges, saidbreech casing having a pair of longitudinal tubes in the forward end thereof for holding a plurality of projectiles in respective axial alignment with the propelling charges, said breech element having a plurality of parallel tiring chambers so disposed that one of said chambers is in a ring position in axial 4alignment with said barrel when another chamber is in a loading position in axial alignment with one of said propelling charge recesses and tiring chamber aligned therewith in the loading position whilexsimultaneouslyadvancing the leading projectile into the front end of the same' one of said firing chambers, cam means on the inner front and rear wall surfaces of said breech casing for combining the propelling charge and projectile in said loaded firing chamber during the movement thereof from loading to firing position, and baille means secured to and movable with said breech element for preventing the advance of both the propelling charges and projectiles during the movement of said loaded chamber into tiring position.

7. In a gun, a breech casing, a barrel xedly secured in said casing, tiring means in the rear of said casing in axial alignment with said barrel, a breech element having a pluralityV of firing chambers movable from loading to tiring position in response to the discharge of a round of ammunition, said breech casing having a longitudinal recess in the rear 'end thereof for holding a plurality of cartridge cases, said breech casing having a longitudinal.

tube projecting forwardly therefrom for holding a plurality of projectiles in axial alignment with said cartridge case recess, means for advancing the leading cartridge case into lthe rear end of one of said firing chambers when in the loading position thereof while simultaneously advancing the leading projectile into the front end 0f the same one of said firing chambers, cam means on the inner front and rear surfaces of said breech casing for combining the cartridge case and projectile in said loaded firing chamber during the movement thereof from loading to firing position, and an obturating sleeve slidably mounted in the front end of each of said firing chambers for forward movement into engagement with the front end wall' of said breech casing to seal the interior of said breech casing against the entry of the gases generated by the discharge of a round of ammunition in said ring chamber.

8. In a gun, a breech casing, a barrel fixedly secured in said casing, firing means in the rear of said casing in axial alignment with said barrel, a breech element slidably mounted in said breech casing for transverse movement therein in response to the discharge of a round of ammunition, said breech casing having a pair of longitudinal recesses in the rear end thereof for holding a plurality of propelling charges, said breech casing having `a pair of longitudinal tubes in the forward end thereof for holding a plurality of projectiles in respective axial alignment with the propelling charges, said breech element having a pair of parallel firing chambers so disposed that one is in a firing position in axial alignment with said barrel when the other is in a loading position in axial alignment with one of said propelling charge recesses and the corresponding projectile tube, means for advancing the leading propelling charge into the rear end of said firing chamber aligned therewith in the loading position while simultaneously advancing the leading projectile into the front end of the same one of said tiring chambers, cam means on the inner front and rear wall surfaces of said breech casing for combining the propelling charge and projectile in said loaded firing chamber during the movement thereof from loading to tiring position, baie means secured to and movable with said breech element for preventing the advance of both the propelling charges and projectiles during the movement of said loaded chamber into ring position, and an obturating sleeve slidably mounted in the front and rear ends of each of said firing chambers for outward movement relative thereto into respective engagement with the front and rear end Walls of said breech casing to seal the interior of said breech casing against the entry of the gases generated by the discharge of the round of ammunition in said firing chamber.

9. The combination defined lin claim 3 wherein said breech casing includes a rearwardly extending venturi portion in axial alignment with said barrel, said venturi portion havingV an enlarged gas expansion area inthe forward end thereof opening into. the interior of said breech casing to form a continuation of each of said firing chambers in the ring position thereof and thereby permit recoilless operation of the gun.

References Cited in the le of this patent UNITED STATES PATENTS Day Aug. 31, 1837 Nichols Sept. 2, 1862 McCullough -..'Nov. 21, 1893 Smith Oct. 7, 1902 Chisholm May 9, 1905 Clarke July 18, 1905 10 Smith Nov. 30, 1909 Storle June 1,y 1920 Pope Mar. 23, 1948 Fowler Dec. 27, 1949 Hurt June 10, 1952 FOREIGN PATENTS Germany Oct. 16, 1900 Great Britain Apr. 17, 1919 Great Britain Nov. 14, 1947 Great Britain Nov, 28, 1949V 

